1570s, "pertaining to a bulb," from Latin bulbosus, from bulbus (see bulb). The meaning "bulb-shaped" is recorded from 1783. Related: Bulbously; bulbousness. Bulbaceous is from 1731.
Entries linking to bulbous
bulb n.
1560s, "an onion," from French bulbe (15c.), from Latin bulbus "bulb, bulbous root, onion," from Greek bolbos "plant with round swelling on underground stem." It was extended 1660s to "spherical underground part of an onion, lily, etc." It had expanded by 1800 to "swelling in a glass tube" (thermometer bulb, light bulb, etc.).